Hydrothermal explosion

Hydrothermal explosions occur when superheated water trapped below the surface of the Earth rapidly converts from liquid to steam, violently disrupting the confining rock.

Hydrothermal explosions are caused by the same instability and chain reaction mechanism as geysers but are so violent that rocks and mud are expelled along with water and steam.

A sudden reduction in pressure causes a rapid phase transition from liquid to steam, resulting in an explosion of water and rock debris.

[4] Yellowstone National Park is a thermally active area with an extensive system of hot springs, fumaroles, geysers, and mudpots.

Rarely has any steam explosion violently hurled water and rock thousands of feet above the ground; however in Yellowstone's geological history these colossal events have been recorded numerous times and have been found to have created new hills and shaped parts of the landscape.

What triggered this series of events has not yet been clearly established, but volcanologists believe a large earthquake could have played a role by accelerating the melting of nearby glaciers and thus depressurizing the hydrothermal system.

[7] On 23 July 2024, a small hydrothermal explosion was witnessed by several tourists coming from the Black Diamond Pool hot spring in Biscuit Basin.

[11] The explosion, probably caused by a change in the plumbing under the hot spring, launched a plume of water and rock fragments 400–600 feet (120–180 m) into the air.